The most dominant, disturbing turbulence is an axial circulation with a heavy turbulence around the tip of the blading at the end wall in the pumps suction side such as indicated by the arrows in FIG. 1. There are two major reasons for this flow, one is the bladings inherent tendency to act as a screw conveyor and the second is the pumps differential pressure, which tends to push the liquid back through the pump from the discharge side towards the suction side. When this flow of liquid meets with the stationary end plate, the friction between the end plate and liquid causes a reduction in the liquid particles velocity, which has a further increasing effect on the turbulence. This effect is most noticeable at the pumps suction side, but it occurs also to a lesser degree at the discharge side.
Further this type of pump is among other things typical in that an axially cross section through the rotor shows the blades (or worm turns) cross section being perpendicular to the axle.
This position of the blades which is commonly known from each and every screw conveyor is however the cause of a substantial loss of power when used in a pump of the types dealt with.
The best, i.e., the working condition results in a minimum loss of power for such a pump, is a condition where each and every particle in the liquid ring follows a complete circular pattern in a cross section perpendicular to the axle.
The eccentricity of the liquid ring with respect to the rotor result however is that there between the turn of the liquid particles and the work occurs a relative motion which breaks the liquid ring twice per revolution and which thereby results in a great loss of power.